Search results
Results From The WOW.Com Content Network
The default route is generally the address of another router, which treats the packet the same way: if a route matches, the packet is forwarded accordingly, otherwise the packet is forwarded to the default route of that router. The route evaluation process in each router uses the longest prefix match method to
Cisco's implementation of traceroute also uses a sequence of UDP datagrams, each with incrementing TTL values, to an invalid port number at the remote host; by default, UDP port 33434 is used. An extended version of this command (known as the extended traceroute command) can change the destination port number used by the UDP probe messages.
Packet Tracer is a cross-platform visual simulation tool designed by Cisco Systems that allows users to create network topologies and imitate modern computer networks. The software allows users to simulate the configuration of Cisco routers and switches using a simulated command line interface.
default or static routes that are manually configured, [3] [4] on-demand routing, [5] dynamic routing protocols, [6] or; Policy-based routing. [7] In a small network such as a home or home office, a default route is often used to send all traffic to the user's Internet service provider.
ppp0 is a PPPoE interface, which is configured as the default route in this example. A default route is recognized by the destination 0.0.0.0 and the flag G. A network router is identified by the network mask 255.255.255.255 and the flag H.
In this case, the longest prefix of the candidate routes is 192.168.20.16/28, since its subnet mask (/28) is longer than the other entry's mask (/16), making the route more specific. Forwarding tables often contain a default route , which has the shortest possible prefix match, to fall back on in case matches with all other entries fail.
Once a route has been selected, the routing information database is updated. If two routes have the same administrative distance, the router uses its vendor-specific algorithm to determine which route should be installed. [2] Cisco routers simply ignore the values and fall back to the default values, which are never the same. [4]
The tool is often used for network troubleshooting. By showing a list of routers traversed, and the average round-trip time as well as packet loss to each router, it allows users to identify links between two given routers responsible for certain fractions of the overall latency or packet loss through the network. [4]